1. Field of the Invention
The present invention relates to a novel nucleotide oligomer and nucleotide polymer, to nucleosides which can be used as raw materials or intermediates in the synthesis of this nucleotide oligomer and nucleotide polymer, and to functional substances (in the present invention, a functional substance is one having affinity for a target) which exhibit high affinity and/or recognition specificity for a variety of targets and which are applicable to drugs, drug delivery, biosensors, controlling the expressed amounts of genes, curing diseases caused by genetic abnormalities, elucidating the functions of proteins translated by genes, developing reaction catalysts and the like, and which are particularly suited to analysis, screening and the like of proteins, and to a manufacturing method therefor.
2. Description of the Related Art
As biotechnology advances, the focus of interest among researchers and scientists is shifting from genes to analysis of proteins which are the product of genes. Proteins are often analyzed by analyzing substances which have affinity for the proteins.
Consequently, it could be said that a protein can only be analyzed if there is a substance having affinity for that protein. A very large number of proteins to be analyzed are present in cells, and most of their amino acid sequences, structures and the like are unknown, so a variety of substances are needed for analyzing proteins.
At present, however, no efficient method for preparing or obtaining the aforementioned substances for analyzing proteins has been established. The most common method of obtaining a substance having affinity for a specific protein is a method of selecting affinity antibodies using the immune system of an animal. However, because animals are used in this method a large volume of proteins are needed, increasing the number of steps and the costs. Moreover, the affinity antibodies selected and obtained by this method cannot be amplified (that is, replicated). Another problem is that only affinity antibodies having affinity for the same target can be selected. As a result, it is extremely difficult to select individual affinity antibodies having affinity for most types of proteins in cells, and to obtain them in sufficient quantities.
Research has been done into introducing puromycin into the 3′ end of mRNA as a means of synthesizing proteins with genetic information (see for example Japanese Patent Application Laid-open No. 2002-291491 (Claims)). This exploits the fact that puromycin is easily incorporated into proteins because it is mistaken for an amino acid by the translation system. At present, however, incorporation efficiency of puromycin is poor, and only selection of a functional substance from a library of random amino acid 3 residues has been reported.
Meanwhile, methods such as the immunosensor amperometric method have been developed for identifying proteins using antibodies. With this method, as little as 2 ng/L of protein can be measured. However, in such a low-concentration protein solution most of the antibodies are not bound to proteins, and many non-specific reactions occur in solutions (such as serum) containing many impurities, detracting from measurement precision.
Although viral and other coatable supermolecular assemblies have been proposed (see for example Japanese Patent Publication No. H10-508304 (Claims)), the structures in this case are complex, and none with higher affinity than antibodies for a variety of targets can be efficiently manufactured.